The instant invention relates generally to a motor vehicle's interior structure and the use thereof to mitigate injury to vehicle passengers upon collision or marked deceleration of the vehicle.
Known knee bolsters comprise deformable elements which are fixedly located about the passenger compartment of a vehicle so as to be positioned opposite the knee and tibia of each vehicle passenger when the passenger is normally seated in the vehicle. See, e.g., U.S. Pat. No. 3,947,056 issued March 30, 1976 to Schwanz. Upon a collision or marked deceleration of the vehicle, such knee bolsters collapse in a controlled manner to absorb a portion of the kinetic energy of the vehicle passenger to slow same, thereby reducing the severity of passenger injuries sustained during the event.
Significantly, the position and angle of such fixed knee bolsters in relation to the knees and tibiae of each passenger at the time of collision or marked vehicle deceleration have a major effect of the stresses applied to the limbs of the passenger and, hence, the potential for injury. Since such fixed knee bolsters are optimized for passengers of average size, the protection afforded by such knee bolsters becomes increasingly unavailing to passengers whose size deviates from the norm. For example, a 5th percentile female will typically slide under the knee bolster, while a 95th percentile male is likely to suffer substantial injury from knee contact with irregularly shaped dashboard contours and/or vehicular controls situated above the knee bolster. Moreover, such fixed knee bolsters fail to accommodate even an average-sized passenger (1) when the passenger places his feet so as to cause the angle formed between the surface of the knee bolster and either of his tibiae to deviate from the ideal angle to be formed therebetween; (2) when the passenger shifts either of his legs to cause the spacing between the surface of the knee bolster and his tibiae to deviate from the ideal spacing therebetween; or (3) when the passenger shifts his legs so as to raise either of his knees above the knee bolster.
The prior art further teaches the use of knee bolsters in conjunction with an active passenger restraint, such as an air bag, to further restrict the passenger's movement relative to such other restraint, such as to prevent the "submarining" of the passenger beneath the air bag during a crash condition. In this manner, the effectiveness of the active restraint in preventing the serious injury to vehicle passengers is significantly increased. Such auxiliary knee bolsters typically comprise a secondary air bag deployable to engage the knees of the vehicle occupant prior to, or simultaneous with, deployment of the primary (torso) bag. See, e.g., U.S. Pat. No. 3,768,830 issued Oct. 30, 1973 to Hass, teaching a secondary air bag deployed to engage the knees of the vehicle occupant prior to deployment of the primary air bag; and U.S. Pat. No. 3,767,225 issued Oct. 23, 1973 to Mazelsky, teaching a knee bolster comprising a bag-within-a-bag positioned opposite the knees of the vehicle occupants and inflated simultaneously therewith. Alternatively, U.S. Pat. No. 4,198,075 issued April 15, 1980 to Kob et al. teaches a deformable knee impact plate which is pivotally deployed into a position near the knees of the passenger as by an air bag or belt tensioner upon the detection of a crash condition by suitable sensor means. Unfortunately, as with the fixed knee bolsters discussed hereinabove, such auxiliary knee bolsters are optimized for passengers of average size and present similarly increased likelihood of passenger injury when the passengers legs are shifted from their ideal position relative to the knee bolster prior to the deployment thereof upon the detection of a crash condition.
What is needed is a self-adjusting knee bolster whose position within the vehicle relative to the knees and tibiae of a passenger therein continuously adjusts to provide the passenger optimum protection against injury in the event of a subsequent collision or marked vehicle deceleration.